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Author Topic: Smoothstepper loses communication when limit is triggered  (Read 8094 times)

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Offline Jeff_Birt

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Re: Smoothstepper loses communication when limit is triggered
« Reply #10 on: February 24, 2010, 12:20:41 PM »
Look in the main configuration screen in the upper middle section. There is a checkbox for 'Keep charge pump on in Estop'.
Happy machining , Jeff Birt
 
Re: Smoothstepper loses communication when limit is triggered
« Reply #11 on: February 24, 2010, 01:37:43 PM »
Hmm-so Phil says you don;t need the charge pump with the SS. But the charge pump cuts off more than the pulses to the motors. The way I have it wired is it will cut all power to the spindles, and generally stop everything, if the charge pump drops out. This way, if the path from Mach-to the SS-thru my BOB, to the C4 Charge Pump board is not right, everything stops.

If I enable the "charge pump on in Estop", that means I will no longer have that safety built in-I will instead rely on Mach controlling the outputs for an estop, or the SS stopping everything if there is a problem or loss of communication with Mach. It dozen;t seem near as good to me. What am I missing?

Offline Jeff_Birt

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Re: Smoothstepper loses communication when limit is triggered
« Reply #12 on: February 24, 2010, 02:18:16 PM »
The charge-pump IS NOT a safety device. There is no guarantee that when a charge pump signal is present (whether through Mach's LPT drive or the SS) that the PC or SmoothStepper is functioning properly. The Charge-Pump signal was implemented for the parallel port so that devices hooked to it did not jump as a PC was being turned on/off and the LPT pins were in an unknown state. It is only a signal that says, 'Hey mach is not running and controlling this port.'. It is an 'Enable,' but it is not a safety. It would be fine to use for an enable line, in other words the charge pump signal has to be present before certain things can turn on, but just don't depend on it to turn the power to things off in case of emergency.
Happy machining , Jeff Birt
 
Re: Smoothstepper loses communication when limit is triggered
« Reply #13 on: February 24, 2010, 03:07:27 PM »
Jeff:

That's a good point-but I think you may be missing the points I am trying to make.

I am not "relying on" the Charge pump signal as a safety device. The Charge Pump Sensor contacts are wired in series with the (2) physical E-stop switches on my machone. If any of the contacts drops out, then the machine is essentially shut down, by removingthe enables from the Geckos and the BOB's, as well as switching the AC power to the stepper supply, and the spindle drive. I'm not sure how I would be "more safe" to have the charge Pump signal stay on during an E-stop.

and of course, the problem behavior that I reported is NOT occurring on the actual Estop/limit event. It is occurring when I RESET the controller box, without first pressing the on-screen Mach3 RESET button.

I will do more tests to see if things change with "Charge Pump ON in Estop" enabled.
Re: Smoothstepper loses communication when limit is triggered
« Reply #14 on: February 24, 2010, 04:20:32 PM »
Quote
I will do more tests to see if things change with "Charge Pump ON in Estop" enabled.

OK, I can't easily test this. The way my controller box is set up, the charge pump signal directly enables the BOB(built-in detector circuit), and also closes a contact on the external CNC4PC C4 Charge Pump Sensor. When closed, this contact, along with the 2 hardwired Estop switches, will allow 5VDC into the ESTOP pin on the BOB.

I have separate momentary pushbutton switches which allow me to get out of the "bootstrap loop" of having the Charge Pump off while the Estop input is low, but needing the Charge Pump signal in order to get the Estop to go high.

Checking "Charge Pump Active during Estop" just means the machine cycles in and out of a reset condition.



So what I really want to know, is why does pressing the onscreen RESET buttom before I press my hardwired reset pushbutton let the SS continue to function, while if I just press the hardware reset button(applying 5VDC to the Estop input on the BOB), the SS will stop communication?